Method of producing bellows units



June 15, 1937. w. B. CLIFFORD 2,083,943

METHOD OF PRODUCING BELLOWS UNITS Filed March 19, 1955 If: M W

'Wiinems Patented June -15, 1937 Walter B. Clifford, Boston, Mass.,

assignor to Clifiord Manufacturing 00., Boston, Mass, a

The present invention relates to a method of producing a bellows unit suitable 'for use either as a thermostat, a seal orsimilar purposes for which said unit may be employed.

The principal purpose and object of the inventicn is to produce a bellows unit having an attaching flange at the open end by a new, simplified and improved method which dispenses with joints and permits the formation of the flange in the usual process of manufacture of the bellows unit without requiring'a special form of tube or the like.

With this and similar objects in view, the invention consists primarily in the production of a substantially enlarged flange at the open end of the bellows tube, produced during the formation of the bellows folds by fluid pressure. The production of this enlarged, fold at the open end is accomplished in thepre'ferred and simplified form of the invention by pre-rolling a series. of grooves in the tube to locate the forming members, the bulk of the grooves being uniformly spaced to determine bellows folds of uniform diameter and characteristics, the two groovesgat the end of the tube which determine the end fold having a spac the production of bellows folds with fluid pres sure; Fig. 3 is a view of the same tube substantially atthe completion of the operation; Fig. 4

is aviewlof the finished unit with the enlarged,

fold readyfor severance; andFig. 5 is a view of the completed unit illustrating the manner in which it may be assembled within a housing through the employment of the integral attaching flange. v

Referring, particularly to theillustrated embodiment of the invention, the tube as shown in Fig. -1 is what is known as a thin wall cupped tube formed from a sheet of the desired .thick- ,ness by a series of cupping and'drawing' operations. This tube, which is provided with a peripheral wall of uniform thickness and a bottom portion of somewhat greater thickness deterruined by the initial thickness of the sheet, is of corporation of Delaware Application March 19, 1935, Serial No.

3 Claims. (01. 113-116) the form commonly and universally employed for the production of bellows units. The tube in-. dicated at in may have the integral bottom or end wall indented to provide a centrally disposed recess I2, as indicated. The purpose of this formation, which may be varied-as desired, is to i'acilit'ate securing operating members in accurate relationship to the end of the bellows for any desired service. v

After the'formation of the bottom wall and its conversion if desired from'the initial flat condition and the tube is formed, the 'peripheral'wall of the tube is provided with a series of depressed and uniformly spaced grooves or: recesses it, which mark off the wall of the tube and determinethe number and diameter of the resulting bellows folds. As will be-noted from Fig. 2,

these grooves are uniformly spaced from the closed end of the tube lengthwise thereof, and in addition a groove. l6 isform'edin the tube adjacent the open end which has a spacing from the next adjacent groove M which is substantially greater than the spacing of the intermediate grooves. The spacing between the last two grooves may be indicated at l8, and the uniform spacing as I9- By virtue of this wider spacing the formation of bellows folds through, fluid pressure creates a series of uniform folds lengthwise of the tube wall, and a substantially enlarged fold. adjacent the open end, as more particularly indicated in Fig. 3, where the uniform or working folds are indicatedat 20, and the enlarged or attaching fold at 22. Referring again'to Fig. 2, it will be evident that the pr'e-rolled or grooved tube is inserted within a series of forming members 24, which are located within the grooves and have their position determined thereby. The tube mounted within the members is'engaged at the closed end by a contractlng member 26, and at its open end by a source of fluid pressure constituting a head 28 provided with a fluid pressure passage 30. The head 28 slides within and supports-the extended portion 32 of the tube wall-beyond the groove IB, and bears againstthe shoulder formed by the groove. The outer portion of the wall may be engaged and held in sealing engagement with the cylindrical head by fingers 34.

With thetube so assembled and held, fluid. pressure'is introduced thereinto through the head to first bulge the tube between the forming members, and to thereafter form and complete bellows folds through maintenance of the fluid pressure and simultaneous contraction of the tube lengthwise. -At the completion of the operation the bellows unit assumes approximately the shape and condition shown in Fig. 3.

The pre-rolling of the tubes with subsequent forming may be carried out approximately as'indicated in my earlier Patent No. 1,842,148, dated January 19, 1932, and the apparatus employed -for forming may be that described in my Patent I portion 52 is provided with a circumferential No. 1,880,184, dated September 27, 1932; employing the clutch mechanism at the fluid pressure end shown in my Patent No. 1,865,678 dated July.

7 At the completion of the bellows formation.the cupped unit is substantially as shown in Fig. 5, having a series of uniform folds extending from the closed end and terminating in a substantially larger fold which may serveeifectivelyas an attaching flange. It is preferable that the en- I larged fold when 'serving as an attaching flange be severed and this; may be conveniently accomplished along the plane AA of Fig. 4, the outer convolution being engaged by the point of a cutting or skiving tool which severs the open end of the bellows, leaving the extended and in-' tegral flange 50, as indicated. This flange forms an ideal attaching means due to its freedom from'solder joints, and as anlexampleof the manner in which the unit may be employed and anchored through the flange, an. outer housing seating shoulder 54 in which the flange 50 is received and flts,'the upturned edge 56 fitting the recess and aiding in the accurate positioning of the unit within the housing. The opposite side of 'the flange may,'if desired, be engaged housing at the 40 rated.

by a ring 58 which has sufllcientsurface contact withthe flange itselfto reenforce and prevent undue flexing of the flange in use. -The whole assembly may be anchored and sealedto the n will be understood that the hated of attaching thebellows unit at .the open end to a support through a radial flange has been disclosed and usedheretofore, but in all'cases commercially such a flange'has been separately attached, requiring the.use of a'joint which pre-' sented a source of weakness at the point of flexure. It has also been suggested that the tube from which the bellows'unit is made be formed with a radially extending flange. .However, ex-

perience has indicated that in the case of the latter suggestion the'production of such a flange in the forming of the tube and its retention durlng'the forming of the bellowsis not a satis: factory or practical expedient, and as the result, although many such suggestions have heretofore been made, in no case so far as I am aware have they represented a contribution to the practical manufacture of such units. In the case of the present-invention, no modification in'the forming of the tubeis required, the tube being tge standard tube .commonly employed, and t e production of the enlarged fold at the open end is accomplished in the regular formation of bellows folds without additional time or expense or requiring unusual or' difficult operations; The fact that the enlarged fold when severed preseats a radial flange, flat throughout its major area, facilitates in thesupport of this flangein rim by a solder joint 60, as indi-. I

use when sodesired. Furthermore, the flange is used in almost precisely the form in which it emerges. from the-forming operation, andbecause it does not require modification in shape or re-working, difficulties otherwise incident to the handling of this thin wall material are com- .pletely avoided.

What is claimed is:- .1. The method of producing a bellows unit with an integral attaching flange at the open. end

which comprises the formation of a series of bellows folds in a thin wall cupped tube uniform in diameter and spaced relation, and an enlarged fold at the open end of the tube which extends radially substantially beyond the outer diameter of the working folds, and splitting the enlarged radial fold through the outer convolution to provide a generally radially extending attaching flange at the open end integral with the tube wall and having a turned-up rim and capable of attachment at its periphery to a suitable support without interference with the flexing of the bellows folds.

2. The method of producing a bellows unit with an integral'attaching flange at the open end which comprises the formation of a series of uniformly spaced and depressed grooves in a thin wall cupped tube with a similar depressed duced internally thereof and endwlse'c'ontracting pressure to produce a series of uniform folds with an enlarged radial fold adjacent the open end, and splitting the enlarged fold at the outer bend to .leave a generally radial and integral flange larger than the remaining folds with a tumedup portion at the end.

3. The method of producing a bellows unit with an integral attaching flange at the open end which comprises the formation of a series of uniformly spaced and depressed grooves in a thin wall cupped tube with a similar depressed groove adjacent, the open end of the tube butv separated,therefrom to permit. engagement oi,

groove by a distance substantially greater than the spacing between the remaining grooves, as-

sembling the grooved tube within forming mem-- bers which engage the grooves, forming bellows folds in the tube through fluid 'pressureintroduced internally thereof'and endwise contracting pressure to produce a 'series of uniform folds with an enlarged radial fold adjacent the open end, splitting the enlarged fold at the outer bend to leave a generally radial and integral flangewith a tumed-up portion at the rim, and assembling the cup-shaped bellows withthe radial flange seated against a supporting shoulder at one side, and with a supporting and retaining member engaging the opposite side of the flange throughout a suflicient area to prevent substantial flexing of the flange during use.

WALTER B.

the' tube and spaced from the next adjacent 

